Essay: Letter to a Young Scientist

Essay: Letter to a Young Scientist

Polypeptide chains within proteins were then thought to have a mixture of regularly folded ­helical and ribboned sections intermixed with irregularly arranged blocks of amino acids. Less than a year before I arrived in England, the nature of the putative helical folds was still not settled, with the Cambridge trio of Perutz, Kendrew, and Sir Lawrence Bragg ­hoping to find their way by building Tinkertoy-like, 3-D ­models of helically folded polypeptide chains. Unfortunately, they got a local chemist’s bad advice about the conformation of the peptide bond and, in late 1950, published a paper soon shown to be incorrect. Within months they were upstaged by Caltech’s Linus ­Pauling, then widely regarded as the world’s best chemist. Through structural studies on dipeptides, Pauling inferred that peptide bonds have strictly planar configurations, and in April 1951, he revealed to much fanfare the ­stereochemically pleasing alpha helix. Though Cambridge was momentarily stunned, Max Perutz quickly responded using a clever crystallographic insight to show that the chemically synthesized polypeptide ­polybenzylglutamate took up the alpha-helical conformation. Again the Cavendish group could view itself as a major player in protein crystallography.

The unit’s resident theoretician was by then the physicist Francis Crick, who at 35 was two years younger than Max Perutz and one year older than John Kendrew. Francis was of middle-class, Nonconformist, Midlands background, though his father’s long-prosperous shoe factories in Northampton failed during the Great Depression of the 1930s. It was only with the help of a scholarship from Northampton Grammar School that Francis moved to the Mill Hill School in North London, where his father and uncle had gone. There he liked science but never pulled out the grades required for Oxford or Cambridge. Instead he studied physics at University College London, afterwards staying on for a PhD financially sponsored by his Uncle Arthur, who after Mill Hill had chosen to open an antacid-dispensing pharmacy instead of joining the family shoe business.

Unlike Max and John, who came into science as chemists and now held PhDs, Francis had not completed his doctorate. He had done just two years of thesis research, winning a prize for his experimental apparatus to study the viscosity of water under high pressure and temperature, when the advent of the war moved him to the Admiralty. He joined the high-­powered group set up to invent countermeasures against German magnetic mines, and in 1943, his boss, the Cavendish-trained nuclear physicist Harrie Massey, gave him the challenge of combating the German navy’s latest innovation. In great secrecy, ­German shipyards had under construction a new class of mine sweepers ­(Sperrbrechers) whose bows were fitted with huge 500-ton electromagnets designed to trigger ­magnetic mines lying a safe distance ahead. Crick came up with the clever idea that a specially designed insensitive mine would not explode until a Sperrbrecher passed directly over it. By the end of the war, more than 100 ­Sperrbrechers were so sent to the bottom of the ocean.

After Harrie Massey left to lead the British uranium effort at Berkeley, the Cambridge mathematician Edward Collingwood became Francis’s mentor. He saw Francis as both a friend and an invaluable colleague, inviting him for weekends to his large ­Northumbrian home, Lilburn Tower, and taking him to Russia in early 1945 to help decipher the workings of a just-captured German acoustic torpedo.

After the war’s end, Francis’s new bosses did not need to be as forgiving of his loud, piercing laughter or of the distaste for conventional thinking that often inspired it. Though formally made a member of the civil service in mid-1946, Francis soon lost interest in military intelligence and wanted a bigger challenge. He saw in biology the greatest range of potential problems to engage his inquisitive mind.

Apprised of Francis’s desire for a radical change of course, Harrie Massey sent him along to see the physicist Maurice Wilkins at King’s College London’s new Biophysics Laboratory. After the war, while still in Berkeley, Massey had changed Wilkins’s life by giving him a copy of Erwin Schrödinger’s What Is Life? Its message that the secret of life lay in the gene was as compelling to Maurice as it had been to me, and he soon began to make his move into biophysics. He would join J. T. Randall at St. Andrews and then move with him to London. Immediately he and Francis became friends, with Maurice soon asking Randall to offer a job to Francis. Randall thought better of it, though, correctly seeing Francis as a mind he could not control. The Medical Research Council, mindful of Francis’s high wartime repute, came to his rescue and funded his learning to work with cells at the Strangeways Laboratory on the outskirts of Cambridge.

His task during the next two years at the Strangeways–observing how tiny magnets moved through the cytoplasm of cells–did not win Francis any kudos. At best it was busywork that gave him time to seek out more appropriate challenges. These at last came when he moved his MRC scholarship across Cambridge to Max Perutz’s protein-crystallographic unit. Though his new job was no better paid, it would let him work toward the PhD, by then a prerequisite for meaningful academic positions.